Article
Chemistry, Physical
Zoltan Szakacs, Eric Vauthey
Summary: Excited-state symmetry breaking (ES-SB) is common in multibranched electron donor-acceptor (DA) molecules in polar environments. However, due to the lack of an unambiguous spectroscopic signature in the UV-vis region, electronic transient absorption (TA) has not been the preferred method for real-time observation of this phenomenon.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Shaoting Guo, Wen Liu, Yuling Wu, Jing Sun, Jie Li, Hongyu Jiang, Mengfan Zhang, Senhao Wang, Zuyuan Liu, Long Wang, Hua Wang, Hongbing Fu, Jiannian Yao
Summary: Understanding the structure-property relationships in organic semiconductors is crucial for controlling their photophysical properties and developing new optoelectronic materials. Quadrupolar molecules, donor-acceptor-donor (DAD), have attracted extensive attention in various optoelectronic applications. The comparative study on the excited state dynamics of DA and DAD fluorescence systems reveals that they exhibit similar excited state dynamics, which are attributed to the distinctive excited-state symmetry breaking (ESSB) phenomenon observed in a DAD system.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Eric Vauthey
Summary: The emissive properties of symmetric molecules with multiple donor-acceptor branches are often similar to those of single-branched analogues due to partial localization of excitation on one branch. Understanding this excited-state symmetry breaking (ES-SB) requires real-time monitoring of the process.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Stanislav L. Bondarev, Tamara F. Raichenok, Sergei A. Tikhomirov, Nikolai G. Kozlov, Tatyana Mikhailova, Anatoly I. Ivanov
Summary: A synthesized acridine-dione derivative with a quadrupolar motif was studied for its spectral properties in different solvent conditions, revealing that symmetry breaking is mainly due to the formation of asymmetric strong hydrogen bonds on one side of the molecule. In specific mixtures of solvents, it was found that a certain threshold concentration of methanol is necessary for symmetry breaking to occur, with concentrations below this threshold not leading to fluorescence quenching.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Materials Science, Multidisciplinary
Nitesh Tamang, Prajal Chettri, Bishnu P. Joshi, Swayamsiddha Kar, Vaibhav Mahendrakar, Shailesh Srivastava, Nageswara Rao Golakoti
Summary: By synthesizing and characterizing fullerene derivatives of bischalcones with different cycloalkanone ring sizes, the impact of ring size and substituents on the aryl rings on the nonlinear optical properties was investigated. The application of Claisen-Schmidt condensation reaction and analytical techniques such as UV-Vis, FT-IR, 1H NMR, 13C NMR, and mass spectrometry helped identify compound characteristics. Among the synthesized compounds, 2,6-bis-(4-methoxydibenzylidene)acetone exhibited the highest second harmonic generation efficiency and 2,6-bis-(4-methylthiobenzylidene)cyclopentanone showed the highest third-order nonlinear optical property.
Article
Chemistry, Physical
Wei Zhang, Wenqi Xu, Guoxian Zhang, Jie Kong, Xinmiao Niu, Julian M. W. Chan, Weimin Liu, Andong Xia
Summary: In this study, the intramolecular charge delocalization/localization of a newly synthesized acceptor-donor-acceptor molecule was intensively investigated using femtosecond stimulated Raman scattering and femtosecond transient absorption spectroscopy. The nature of the relaxed S-1 state was found to be strongly influenced by solvent polarity, with symmetric delocalized intramolecular charge transfer characters occurring in apolar solvent and asymmetric localized ICT characters appearing in polar solvent due to solvation. The solvation dynamics extracted from fs-TA were consistent with the time constants obtained by FSRS, but FSRS clearly tracked the excited state intramolecular charge transfer delocalization/localization.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Chemistry, Multidisciplinary
K. Swathi, Meleppatt Sujith, P. S. Divya, P. Merin Varghese, Andrea Delledonne, D. K. Andrea Phan Huu, Francesco Di Maiolo, Francesca Terenziani, Andrea Lapini, Anna Painelli, Cristina Sissa, K. George Thomas
Summary: The phenomenon of excited-state symmetry breaking is often observed in multipolar molecular systems, significantly affecting their photophysical and charge separation behavior. In this study, the intrinsic factors regulating excited-state symmetry breaking in multibranched systems are explored using a combination of experimental and theoretical investigation. It is found that the large Stokes shifts observed in highly symmetric phenyleneethynylenes can be explained by the presence of low-lying dark states, as confirmed by two-photon absorption measurements and TDDFT calculations. In addition, an intense fluorescence emission is observed in these systems contrary to Kasha's rule, and this behavior is explained by a novel phenomenon called symmetry swapping, which describes the inversion of the energy order of excited states as a result of symmetry breaking.
Article
Chemistry, Multidisciplinary
Diana Nelli, Valentina Mastronardi, Rosaria Brescia, Pier Paolo Pompa, Mauro Moglianetti, Riccardo Ferrando
Summary: The growth of pyramidal platinum nanocrystals is caused by the adsorption of hydrogen on {100} facets, which results in a peculiar type of symmetry breaking. The size-dependent adsorption energies of hydrogen atoms on {100} facets hinder the growth of pyramidal shapes only when they are sufficiently large. The absence of pyramidal nanocrystals in experiments without hydrogen confirms the crucial role of hydrogen adsorption.
Article
Chemistry, Physical
Anatoly I. Ivanov
Summary: A model is proposed to explain the effect of H-bonding on charge transfer symmetry breaking in excited quadrupolar dyes. The model suggests that the H-bond strength has a small impact on the symmetry breaking degree, unless the free energy of formation of the weaker H-bond becomes positive.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Chemistry, Physical
Nikolay B. Siplivy, Anatoly I. Ivanov
Summary: We propose a three-level model of symmetry-breaking charge transfer (SBCT) in excited octupolar molecules. This model describes the dynamics of the solvent and the dye in the excited state. We introduce a distribution function in the space of two reaction coordinates and derive an evolution equation for this function. We calculate the free energy surface and discuss the conditions for the occurrence and nature of SBCT.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Ivan F. Antipov, Anatoly I. Ivanov
Summary: This theoretical study examines the manifestations of charge transfer symmetry breaking in excited quadrupolar molecules in optical spectra. The research shows that symmetry breaking and solvent fluctuations have an impact on the dipole moments in the ground and excited states of the molecules, with significantly larger effects on the emission dipole moment. The findings also reveal the influence of polar solvent fluctuations on transition dipole moments associated with excited state absorption, in line with available experimental data.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Chemistry, Physical
Koushik Mondal, Subrata Biswas, Ashim Pramanik, Dipanjan Banerjee, Venugopal Rao Soma, Anil Kumar Chaudhary, Pathik Kumbhakar
Summary: Graphene-based 2D materials show strong nonlinear optical responses after suitable modification. Incorporating Au and Ag nanoparticles into graphene oxide nanosheets results in high NLO response with larger absorption coefficient compared to pure graphene and graphene quantum dots.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Pragya Verma, Mariusz Tasior, Palas Roy, Stephen R. R. Meech, Daniel T. T. Gryko, Eric Vauthey
Summary: In polar environments, most quadrupolar dyes behave like their dipolar counterparts when photoexcited. This is due to excited-state symmetry breaking (ES-SB) where the electronic excitation localizes on one side of the molecule. In this study, two A-D-A dyes containing different acceptor groups were investigated using time-resolved vibrational spectroscopy. The results showed that ES-SB occurs in dyes with cyanophenyl acceptors but not with dicyanovinyl acceptors, attributed to differences in electronic coupling between the D-A branches.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Francesco Bertocchi, Andrea Delledonne, Guillem Vargas-Nadal, Francesca Terenziani, Anna Painelli, Cristina Sissa
Summary: Aggregates of cyanine dyes are investigated for their tunable spectral properties in this study. The study presents a joint experimental and theoretical analysis of different types of aggregates formed by a family of cyanine dyes. The analysis rationalizes the optical spectra using an essential-state model that takes into account intermolecular interactions, molecular polarizability, and vibronic coupling.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Zoltan Szakacs, Florian Glocklhofer, Felix Plasser, Eric Vauthey
Summary: This study investigates excited-state symmetry breaking in a series of symmetric 9,10-dicyanoanthracenes with electron-donating groups linked at different positions via various spacers. The results show that as the donor-acceptor distance increases, electronic excitation becomes unevenly distributed.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Optics
Tanvi Karpate, Grzegorz Stepniewski, Dariusz Pysz, Anupamaa Rampur, Yuriy Stepanenko, Ryszard Buczynski, Mariusz Klimczak
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2020)
Article
Engineering, Electrical & Electronic
Bernard Piechal, Jan Szczepanek, Tomasz M. Kardas, Yuriy Stepanenko
Summary: The control of ultrafast laser oscillator repetition rate is crucial for laser burst microprocessing, and a tunable period all-PM fiber harmonically mode-locked oscillator is introduced in the article. The operation frequency is limited by the available pump power, but the energy of emitted pulses is independent of the operating frequency.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Correction
Optics
Yihan Li, Naoya Kuse, Antoine Rolland, Yuriy Stepanenko, Czeslaw Radzewicz, Martin E. Fermann
Article
Materials Science, Multidisciplinary
Tomasz Szymborski, Yuriy Stepanenko, Krzysztof Nicinski, Patrycja Piecyk, Sylwia M. Berus, Monika Adamczyk-Poplawska, Agnieszka Kaminska
Summary: Surface-enhanced Raman spectroscopy (SERS) faces challenges in finding cost-effective and versatile platforms with high enhancement factor. In this study, silicon-based SERS platforms were fabricated using laser ablation, demonstrating high uniformity and stability. The platform showed excellent sensitivity and reproducibility, making it a promising tool for detection and differentiation between fungal and bacterial pathogens.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Chemistry, Physical
Marcin Pastorczak, Michal Nejbauer, Naoki Shinyashiki, Masanobu Takatsuka, Gonzalo Angulo, Yuriy Stepanenko, Czeslaw Radzewicz
Summary: The study observed for the first time the sub-nanosecond stage of the coil-to-globule transition of a polymer in water, which was made possible by a novel experimental approach. The increase in light scattering intensity around 300-400 ps after a temperature jump above the LCST suggests the rapid formation of local nuclei along the polymer chain in the observed stage of the transition.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Optics
Katarzyna Krupa, Tomasz M. Kardas, Yuriy Stepanenko
Summary: This study demonstrates the real-time observation of double-Hopf-type breathers in an erbium-doped fiber laser and discusses their possible explanation. It provides important insights for understanding laser physics and optimizing fiber cavity design.
LASER & PHOTONICS REVIEWS
(2022)
Article
Biochemistry & Molecular Biology
Sylwia Magdalena Berus, Monika Adamczyk-Poplawska, Katarzyna Gozdzik, Grazyna Przedpelska, Tomasz R. Szymborski, Yuriy Stepanenko, Agnieszka Kaminska
Summary: Accurate identification of vaginal microorganisms is crucial for understanding the transition from beneficial symbiotic to pathogenic bacteria and the pathogenesis of vaginal bacterial vaginosis and infections. This study utilized surface-enhanced Raman spectroscopy (SERS) to compile spectral signatures of important vaginal microorganisms and pathogens, contributing to the development of a spectral SERS database. The results showed unique spectral fingerprints for each microorganism, allowing for discrimination between different species. Furthermore, Partial Least Squares Regression (PLSR) revealed discriminating variables for specific compounds in the outer structure of microorganisms, which could be used as marker bands in clinical analysis.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Materials Science, Multidisciplinary
Bogusz Stepak, Natalia Grudzien, Katarzyna Kowalska, Yuriy Stepanenko, Michal Nejbauer
Summary: Glass cleaving by Bessel-like beams is a leading technique for high processing throughput and high edge quality. It has great potential in the production of flat panel displays, camera windows, and medical devices. The controlled weakening of transparent materials and the direction-independent cutting are achieved through proper temporal pulse shaping. The setup does not require any active components in the beam path.
JOURNAL OF LASER APPLICATIONS
(2023)
Article
Optics
Tanvi Karpate, Grzegorz Stepniewski, Tomasz Kardas, Dariusz Pysz, Rafal Kasztalanic, Yuriy Stepanenko, Ryszard Buczynski, Katarzyna Krupa, Mariusz Klimczak
Summary: We present a multidimensional characterization of femtosecond pulse nonlinear dynamics in a tellurite glass graded-index multimode fiber. We observe novel multimode dynamics of quasi-periodic pulse breathing, which exhibits recurrent spectral and temporal compression and elongation induced by changes in input power. This effect is a result of the power-dependent modification of the excited mode distribution, leading to modified efficiency of nonlinear effects. Our findings provide indirect evidence for periodic nonlinear mode coupling in graded-index multimode fibers via Kerr-induced dynamic index grating.
Article
Chemistry, Physical
Grzegorz Stepniewski, Pascal Hanzi, Adam Filipkowski, Monika Janik, Mariusz Mrozek, Yuriy Stepanenko, Robert Bogdanowicz, Valerio Romano, Alexander Heidt, Ryszard Buczynski, Mariusz Klimczak
Summary: The integration of nanodiamonds with optical fibers has been shown to be a compelling methodology for magneto-optics. This study reveals that nanodiamonds can be utilized for nonlinear optics by manipulating the nonlinear response of glasses. The experiments demonstrate a reduction in the nonlinear refractive index of materials containing nanodiamonds, providing a guideline for future research on negative nonlinearity fibers.
Proceedings Paper
Nanoscience & Nanotechnology
Michal P. Nowak, Bogusz Stepak, Mateusz Pielach, Yuriy Stepanenko, Tomasz Wojciechowski, Bartosz Bartosewicz, Urszula Chodorow, Przemyslaw Wachulak, Piotr Nyga
Summary: This study demonstrates the generation of structural plasmonic colors through femtosecond laser-induced modification of thin semicontinuous aluminum films. The method allows for the production of surfaces with stable and vibrant colors. The effects of laser parameters on the final color are also explored.
Article
Computer Science, Information Systems
Mateusz Pielach, Jan Szczepanek, Katarzyna Krupa, Yuriy Stepanenko
Summary: This Letter presents an ultrafast dispersion-managed all-polarization-maintaining fiber oscillator modelocked with a chirped fiber Bragg grating, allowing precise tuning of net cavity dispersion and delivering stable ultrashort pulses.
Proceedings Paper
Engineering, Electrical & Electronic
Katarzyna Krupa, Tomasz M. Kardas, Yuriy Stepanenko
Summary: Experimental evidence shows the presence of breathing-like dynamics in an all-normal dispersion all-PM Ytterbium-doped fiber laser. The pulsation period oscillates with increasing pump power until a stationary dissipative soliton is formed.
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Mateusz Pielach, Bernard Piechal, Jan Szczepanek, Piotr Kabacinski, Yuriy Stepanenko
Summary: In this work, we introduce an all-polarization-maintaining, all-large-mode-area fiber laser oscillator which is passively mode-locked using a nonlinear optical loop mirror. The system, doped with ytterbium, operates at a central wavelength of 1.03 μm and emits 12 nJ pulses at a repetition rate of 7.56 MHz. The positively chirped pulses from an all-normal-dispersion cavity can be externally compressed to 250 fs in duration.
FIBER LASERS XVIII: TECHNOLOGY AND SYSTEMS
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Bernard Piechal, Jan Szczepanek, Tomasz M. Kardas, Mateusz Pielach, Yuriy Stepanenko
2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS PACIFIC RIM (CLEO-PR)
(2020)